Roller bit



Jan. 19, 1937. A. c. CATLAND 2,068,375

ROLLER BIT Filed May 25, 1935, 2 Sheets-Sheet 1 Jan. 19, 1937. c, c D I 2,068,375

ROLLER BI-T Filed May 25. 19-35 2 Sheets-Sheet 2 AILFREDI C. CM'LAND 1mm ATTORNEY Patented Jan. 19,1937

UNITED STATES PATENT OFFICE 14 Claims. (01. 255-71) This invention relates to a well drilling tool and has particular reference to a roller bit for use in ,the rotary method of well drilling. A general object of this invention is to provide an improved roller bit that is inexpensive and that is very rapid and efiicient in operation.

Another object of the invention is to provide a roller bit embodying three circumferentially spaced roller cutters for cuttingthe well bore to gauge and for drilling the outer portion of the Well bore and a pair of inner cutters for drilling the inner portion of the bore, the inner and outer roller cutters being related to provide for the steady efiicient operation of the bit.

Another object of this invention is to provide a roller bit of the character mentioned embodying a novel and dependable means for mounting and retaining the several rotatable roller cutters.-

Another object of the invention is to provide a roller bit for well drilling in which all of the wearing parts may be easily and quickly re-' placed at the well or in the field after each run, if necessary, by simple, common tools.

Another object of the invention is to provide a roller bit embodying a single simple cutter support or member that provides a spindle for carrying the inner cutters, that retains the outer cutt'ers on their shafts or spindles, that protects the inner sides of the outer cutters and the bearings and bushings of the outer cutters, and that directs the discharging circulation fluid against the bottom of the well bore and against the cutters.

Another object of the invention is to provide a roller bit in which the circulation fluid is discharged downwardly in a wide stream froin a point adjacent the bottom of the well bore to have an effective hydraulic action in eroding the formation throughout a wide path at the bottom of the bore.

The various objects and features of the invention will be fully understood from the following detailed description of a typical form and application of the invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 is'a side elevation of the bit provided by the present invention. Fig. 2 is an enlarged bottom elevation of the bit.- Fig. 3 is an enlarged fragmentary vertical detailed sectional view taken substantially as indicated by line 33 on Fig. 1. Fig. 4 is an enlarged'fragmentary vertical detailed sectional view taken substan-' tially as indicated by line 4-4 on Fig. 2. Fig. 5 is a bottom elevation view showing the outer cutters and their bearings in position with the cutter mounting and retaining member and the inner cutters removed. Fig. 6 is a side eleva-' tion of the cutter mounting and retaining member apart from the bit andFig. '7 is a top or 5 plan view of the said member.

The improved roller bit provided by my invention includes, generally, a shank I0, spaced outer cutters A, B and C carried by the shank l0, a removable member H attached to the shank Ill, 10

and inner cutters D carried by the member II.

The body or shank ID of the bit is adapted to be connected to the lower end of a well drilling string and is provided and formed to carry the cutters A, B and C and the member II. The major portion I2 of the shank- I0 is. cylindrical and is provided at its upper end with means for connecting with the drilling string. In the particular case illustrated in the drawings a screw threaded pin I3 is provided on the upper end of the shank ID for facilitating its connection with a drill collar or other part of a drilling string. In accordance with the invention downwardly projecting wings or legs M are provided on the lower end of the shank ID for carrying the cutters A and B and .a similar leg l5 projects from the lower end of the shank to carry the cutter C. The legs I4 and I5 project outwardly and downwardly from the lower end portion of the shank l0 and theouter surfaces of the legs are preferably curved to be substantially concentric with the longitudinal axis of the bit. The legs just described are preferably equally spaced one from the other. is preferably fiat and normal to the vertical axis of the shank. The inner side ll of the legs l4 and I5 are inclined downwardly and outwardly with respect to the vertical 'axis of the bit. Shafts or spindles l8 are provided on 0 the legs I4 to carry the cutters A and B and a similar spindle I9 is provided on the leg l5 to support the cutter C. The spindles I8 and I9 are prefarbly integral with their respective legs and project downwardly and inwardly from the 5' inner sides ll of the legs. The longitudinal axis of the spindles l8 and I9 are preferably normal to the inner sides I! of the legs.

The cutters A, B and C are rotatable ontheir respective spindles to cut the well bore to gauge and to drill or form the .outer portion of the well bore. The outer cutters A, B and C are in the nature of substantially cylindrical roller cutters provided with peripheral cutting parts or teeth 20. The cutters A and B are compara- The lowerface or end N5 of the shank 35 for free rotation on the bushings 2|.

bearings and bushings from the spindles.

tively narrow while the cutter C is wider to have more extensive engagement with the formation at the bottom of the well bore. The opposite ends of the cutters A, B and C may be flat and normal to the axis of the cutters as illustrated in the drawings. The cutting teeth 20 may be straight and axial and the opposite ends of the teeth 20 of the cutters A, and B may be bevelled away or inclined. The outer ends of the cutting teeth 20 of the large outer cutter C are preferably bevelled to properly engage the formation at the side wall of the well bore while the inner ends of the teeth 20 of this cutter may be straight and may extend to the inner end of the cutter. The cutters A, B and C being rotatable on the spindles l8 and I9 rotate about downwardly and inwardly inclined axes and project downwardly and outwardly beyond the lower 1 ends of the legs l4 and I5 to act on the forma- 20 tion at the side wall and bottom wall of the bore.

Wear taking bushings 2| are provided on the spindles l8 and roller bearings 22 are provided for mounting or carrying the cutters A and B The bushings 2'l arereadily replaceable when worn and are provided at their outer ends with radial flanges 23, for bearing on the inner sides. H of the legs l4. Dowel pins 24 cooperate with notches in the flanges 23 to hold the bushings 2| against rotation. A replaceable wear taking bushing25 is provided on the spindle I9 and the cutter C is rotatable on the bushing through a roller bearing 26. The bushing 25 has a radial flange 21 on its outer end for bearing against the inner side ll of the leg l5. A dowel pin 28 cooperates with a notch in the flange 21 to hold the bushing 25 against rotation. As will be hereinafter described the member receives the inward thrusts from the cutters A, B and C and the bearings .22 and 26 and prevent the displacement of the cutters and their mountli nlg e cutters A, B and C mounted as just described have active engagement with the earth formation to maintain the well bore to gauge. The large outercutter C has substantial engagement with the formation at the bottom of the well bore to make an annular cut as well as aiding in cutting the bore to gauge. The cutters A, B and C in being circumferentially spaced effectively steady and guide the bit.

The member H is provided to carry the inner cutters D and to retain the cutters A, B and C on their respective spindles. The member I also forms a discharge nozzle or device for discharging the circulation fiuid.- The member H is a simple one piece element that can be easily detached from the shank H) to allow the easy removal of the several cutters and their mountings. The member H has flanges 30 at its upper end for bearing upwardly against the lower face l6 of the shank l0. In the construction illustrated there are three flanges 30 projecting radially outwardly between the three spaced legs I4 and I5. Openings or slots 3| are provided in the outer ends of the flanges 30 to receive studs 32 which project from the lower end of the shank. Nuts33 are threaded on thestuds 32 to clamp the flanges 30 against the lower end I6 of the shank and thus attach the member H to the shank. Cotter keys 34 may be provided to lock the nuts'33 against displacement.

The member projects downwardly within the series of legs l4 and I5 and is provided with lateralLv projecting parts 35 and 36. The part 35 has a downwardly and outwardly inclined outer'surface 38 adapted to bear on the end of the bushing 2| carrying the cutter A. The part 35 is sufllciently large to shield and protect the inner side of the cutter A and its bearing 22 and bushing 2|. The part 35 thus retains the cutter A and its bushing 2| and bearings 22 on the spindle l8 and forms an abutment which receives inward end thrusts from the cutter. The part 36 of the member H has a downwardly and outwardly inclined outer face 39 which bears on or engages the inner end of the bushing 21. The part 36 shields and protects the inner side of the large outer cutter C and retains the cutter and its bushing 25 and bearings 26 on the spindle. The surface 39 of the part 36 is adapted to receive inward thrusts from the cutter C and the bearings 26.

The spindle l8 carrying the cutter A has a central longitudinal opening extending to the outer surface of the leg l4. An opening 4| is provided in the part 35 to communicate with the opening 40. A screw 42 extends through the opening 40 and is threaded into the opening 4| to connect the part 35 with the spindle I8.

Thehead of the screw 42 is received in a counterbore' in the outer end of the opening 40. The spindle III has a central longitudinal opening 43 extending inwardly from the outer surface of the leg 15. An opening 44 is provided in the part 36 to register with the opening 43. A screw 45 is arranged through the opening 43 and threaded in the opening 44 to connect the part 36 withthe spindle H. A counterbore at the outer end of the opening 43 receives the head of the screw 45. Cotter pins may be provided to prevent unthreading of the screws 42 and 45. The screws 42 and 45 connect the leg l5 and one of the legs l4 with the member H to strengthen and lend rigidity to the construction.

The member H is provided with a spindle 46 for carryingthe inner cutters 'D. In the preferred form of the invention the spindle 46 is disposed in the same radial or vertical plane as the spindle |8 carrying the cutter B. The spindle 46 extends outwardly from adjacent the central vertical axis of the bit and its outer end may engage the inner end of the spindle I8 which supports the cutter B. The spindle 46 is inclined downwardly and inwardly but at a lesser angle than the said spindle I8. The outer end of the spindle 46 may be received in a socket 41 in the inner end of the spindle IS. A central longitudinal opening 48 extends through the spindle 46 from the inner said of the member H. An opening 49 is provided in the spindle |8 to register with the opening 48. A screw 50 extends through the opening 48 and is threaded in the opening 49 to tie together the spindle 46 and the spindle |8 carrying the cutter B. I

The inner cutters D are provided to act on and cut away the formation at the bottom of the bore within the path or cut made'by the large outer cutter C. In accordance with the invention the inner cutters D have active engagement with the formation from a point adjacent the central vertical axis of the bit to the inner margin of the cut made by the large outer cutter C. The cutters .D are rotatable on the spindle 46 to turn about a downwardly and inwardly inclined axis in the same radial plane as the cutter B. The cutters D are in the nature of substantially frusto-conical roller cutters. Peripheral cutting parts or teeth 5| are provided and axial, as illustrated. In the particular embodiment of the invention shown. in the drawings there are two inner cutters D arranged in end to end relation. The outermost inner cutter D has the largest diameter and the two cutters D are related so that their teeth 5I are adapted to act in a common substantially horizontal plane at thebottom of the well bore. A replaceable wear taking bushing 52 is provided-on the spindle 46 and is provided at its outer end with a fla e 53 to form a thrust washer or member for e cutters D and to shield the cutter B. The flange 53 has a downwardly and outwardly inclined outer surface for engaging the bushing 2i. A pin 54 holds the removable bushing 52 against rotation on the spindle 46. A thrust washer 55 may be provided on the spindle 46 at the inner end of the bushing 52. The flange 53 is adapted to receive the outward end thrusts from the cutters D. Roller bearings 56 may be provided to support the cutters D for free rotation on the bushing 52.

The invention provides novel means for handling the rotary mud or circulation fluid. A central longitudinal fluid passage 51 is provided in the shank ill to conduct the fluid downwardly from the drilling string. The passage 51.;terminates at its lower end in a reduced opening 58. A replaceable bean or nipple 59 is threaded in a socket in the lower end of the opening 58 and projects downwardly beyond the lower end I6 of the shank. A socket 60 in the upper end of the member II receives the projecting portion of the nipple 59. In accordance with the invention the member I I has a main port 6| extending downwardly from the opening 62 of the nipple 59. The main port 6| extends to the lower end of the member II and discharges at a point adjacent the inner end of the spindle 46 and thus conducts the circulation fluid to a point near the bottom of the well bore. The discharge end of the main port 6| is transversely elongated to discharge a wide stream of fluid which effectively. flushes across the bottom of the well bore to have an eroding action and to maintain an effective turbulence in the lower end of the bore. The greater proportion of the circulation fluid discharges from the lower end of the main port El at a comparatively high velocity and has a powerful hydraulic action in eroding and cutting away the formation at the bottom of the bore to increase the cutting ordrilling speed of the bit.

Means is provided for flushing the several cutters. The member II has a reduced port 63 communicating with the opening 62 of the nipple 59 and discharging downwardly above the inner cutters D. The fluid discharged from the port 65 washes the inner cutters D and the adjacent outer cutter B. A reduced port 64 in the member II conducts fluid downwardly from the opening 62 and directs it against the large outer cutter C to flush it free of accumulations or cuttings, etc. A similar port 55 is provided in the member II to discharge a stream of circulation fluid downwardly and outwardly against the outer cutter A. The reduced ports .63, G4 and 65 thus provide for the individual washing or flushing of the several cutters while the main port 6| conducts the major portion of the circulation fluid to a point adjacent the bottom of the well bore to assist in the drilling by eroding or washing away the formation.

In operation the bit is connected with the lower end of a drilling string and is rotated and downwardly and outwardly are particularly.

rapid and eflicient in their cutting engagement withthe earth formation. The inner cutters D are offset from the central vertical axis of the bit to follow a circular or annular path to make an annular cut in the formation. The annular cut made by the inner cutters D extends outwardly from adjacent the center of the bore to v the inner edge of the cut made by the large outer cutter C. Thus the entire bottom wall or substantially the entire bottom wall of the bore is actively engaged by the cutters of the bit. As described above, the circulation fluid discharging under pressure from the main port materially aids in the drilling action.

When the parts become worn after operation they may be easily and quickly removed for replacement. The member II is quickly detached from the shank III by removing the nuts 33 and the screws 42, 45 and 50. These operations can be performed with common or typical wrenches. All the wearing parts of the bit are removable for replacement. The several cutters A, B, C and D and their bushings and bearings, are free for removal upon the detachment of the member II from the shank. Further, if necessary, the member Il may be replaced or repaired. The member II in addition to carrying the inner cutters D protects the inner sides of the outer cutters A and C and forms a thrust member for receiving thrusts from these cutters and their bearings and bushings. The member I I in being connected with the legs l4 and I5 by the screws 42, 45, and 50 is rigidly held in place and rigidly ties together the spaced parts or legs of the bit.

Having described only a typical preferred form and application of my invention, I do not wish 9 to belimited or restricted to the specific details set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

Having described my invention, I claim:

1. A well bit including a shank having a plurality of integral bearings projecting therefrom, an outer roller cutter rotatably carried on each bearing to project below the shank, a member removably attached to the shank and positioned to retain said outer cutters on their bearings, and an inner roller cutter carried by said member to rotate in spaced relation to the outer cutter and act on the formation being drifled within the path of the outer cutter.

as the axis of said outer cutter to act on the formation within the path of the outer cutter.

3. A well bit including, a shank, outer roller cutters rotatably mounted on the shank to act on the formation at circumferentially spaced points to maintain the well bore to gauge, a member removably attached to the shank, a spindle on the member, a bushing on the spindle retaining one of the outer cutters in place, and an inner roller cutter rotatable on the bushing.

4. A well bit including a shank, spaced legs projecting downwardly from the lower end of the shank, inwardly projecting spindles on the legs, roller cutters rotatable on the spindles projecting uniformly radially of the shank to uniformly cut clearance for the bit, a member removably attached to the lower end of the shank and retaining the said cutters on the spindles, and an inner roller cutter carried by the member to act on the formation within the path of the first mentioned cutters.

5. A well bit including a shank, spaced legs projecting downwardly from the lower end of the shank, inwardly projecting spindles on the legs, roller cutters rotatable on the spindles and adapted to act on the formation to maintain the well bore to gauge, a member removably attached to the lower end of the shank, a spindle on the member extending outwardly to engage one of the inwardly projecting spindles, and an inner roller cutter rotatable on the last mentioned spindle.

6. A well bit including a shank, spaced legs projecting downwardly from the lower end of the shank, inwardly projecting spindles on the legs, roller cutters rotatable on the spindles projecting uniformly. radially beyond the shank and adapted to act on the formation to cut clearance for the bit, a member removably attached to the lower end of the shank and retaining the said cutters on the spindles, removable means connecting the spindles and member, and an inner roller cutter carried by the member to act on the formation within the path of the first mentioned cutters.

7. A well bit including a shank, spaced legs projecting downwardly from the lower end of the shank, downwardly and inwardly inclined spindles on the inner sides of the legs, roller cutters rotatable on the spindles so that their outermost cutting parts are equidistant from the central longitudinal axis of the bit and adapted to act on-the formation to cut clearance for the bit, a member removably attached to the lower end of the shank, a downwardly and inwardly inclined spindleon the member, and a roller cutter on the last mentioned spindle for acting on the formation at the bottom of the bore. I

8. A well bit including a shank, spaced legs projecting downwardly from the lower end of the shank, inwardly projecting spindles on "the legs, removable bushings on the spindles, roller cutters rotatable on the bushings and operable to engage the formation to uniformly drill clearance for the bit, a member detachably connected to the shank and retaining the bushings on the, spindles and the cutters on the bushings, and an inner roller cutter carried by the member.

9. A well bit including a shank, spaced legs projecting downwardly from the lower end of the shank, inwardly projecting spindles on the legs, removable bushings on the spindles, roller cutters rotatable on the bushings and operable to engage the formation to drill the bore to gauge, a member detachably connected to the shank and retaining the bushings on the spindles and the cutters on the bushings, screws connecting the spindles with the member, and an inner roller cutter carried by the member.

10. A well bit including a shank, three circumferentially spaced legs projecting downwardly from the shank, spindles projecting inwardly from the legs, outer roller cutters rotatable on the spindles adapted to drill the bore to gauge, a removable member projecting from the shank, parts on the member adapted to receive inward thrusts from two of the said outters, a spindle on the member, a part on the last mentioned spindle adapted to receive inward thrusts from the other outer cutter, and an inner roller cutter rotatably supported on the spindle ofthe member.

11. A well bit including a shank, three circumferentially spaced legs projecting downwardly from the shank, spindles projecting inwardly, from the legs, outer roller cutters rotatable on the spindles adapted to drill the bore to gauge, a removablemember projecting from the shank, parts on the member adapted to receive inward thrusts from two of the said cutters, a spindle on the member, a bushing on the last mentioned spindle adapted to receive inward thrusts from the other outer cutter, and an inner roller cutter rotatable on the bushing to engage the formationat the bottom of the well bore.

12. A well bit including, a shank, roller cutters rotatably carried by the shank to act on the formation at circumferentially spaced points to maintain the well bore to' gauge, a member removably attached to the shank, and an inner roller cutter carried by the member to act on the formation within the path of the outer cutters, there being a fluid passage in the shank and a fluid carrying port formed directly in thel member to communicate with and receive fluid from the passage, the walls of said port acting to confine the fluid and direct it downwardly from a point adjacent the bottom of the well bore to erode the formation.

13. A well bit including a shank, three circumferentially spaced legs projecting downwardly from the shank, spindles projecting inwardly from the legs, outer roller cutters rotatable on the spindles to drill the bore to gauge, a member disposed between the legs, a flange on the member bearing against the lower end of the shank, releasable means clamping the flange against the shank, the member being adapted to receive the inward thrusts from the outer cutters, and an inner roller cutter carried by the member.

14. A well bit including a shank, three circumferentially spaced legs projecting downwardly from the shank, spindles projecting in-v wardly from the legs, outer roller cutters ro tatable on the spindles to drill the bore to gauge, a removable member projecting from the shank, parts .on the member adapted to receive inward thrusts from two of the said cutters, a spindle on the member, a bushing on the last mentioned spindle, a flange on the bushing adapted to receive inward thrusts from the other outer cutter, and an inner roller cutter rotatable on the bushing, the said flange being adapted to receive outward thrusts from the inner cutter.

ALFRED C. CATLAND. 

